In the usual combined AM and FM radio receiver, a coil wrapped around a ferrite rod is utilized as an AM antenna and a separate antenna, such as a telescoping whip in the case of portables or a coupling to the line cord in the case of a table model, is utilized for FM. Frequently, it is desired to use such a radio receiver at a location quite distant from the broadcast station where the aforementioned internal antennas carried by the receiver produce inadequate reception. It is known to provide a pair of terminals coupled to the FM antenna input for accepting an external antenna. It is also known that the reception of an AM radio can be improved with an external antenna connected to a coil which is inductively coupled to the ferrite antenna. However, the problem has not been solved as to how to provide a single pair of external antenna terminals which are useable for both AM and FM bands.
It is an object of the present invention to provide in a conventional AM/FM radio receiver a system for coupling an external antenna for aiding both AM and FM reception.
It is a further object of the present invention to provide a simple and inexpensive means for coupling an external to a radio having the usual separate internal AM and FM antennas.